Process for the construction of monolithic structures of basalt



UNITED STATES PATENT. OFFICE.

FRANCOIS RIBBE, 0F MAURIAC, AND PAUL DRE, 0]! PARIS, FRANCE,

PROCESS FOR THE CONSTRUCTION OF MONOLITHIC STRUCTURES OF BASALT.

1,331,377. No Drawing.

To all whom it may concern I Be it known that we, FRANgoIs RIBBE, of No.26 Avenue de la Gare, Mauriac, Cantal, France, doctor of medicine, andPAUL DH1- of No. 42 ter Rue Notre Dame des Champs,

Paris, France, engineer, and citizens of the -Republ1c of France, haveinvented certain new and usefulImproved Processes for the Constructionof Monolithic Structures of Basalt, of which the following is aspecification.

The French Patent No. 449707 applied for on 29 December 1911 contains adescription of methods of casting, molding and de- V vitrifying on theactual surface of the ground, various articles of basalt that has eenpreviously melted in cupola furnaces more often in one p1ece and ofconsiderable dimensions,'such asdams, sea-Walls, piers, bridges,fortifications etc.

Hereinafter a description is given by way of example, of the manner ofconstructing a dam for damming a stream.

The shape of the structure has nothing peculiar in it. Nevertheless ingeneral it is advisable to'arrange that the basalt shall act incompression. The structure will therefore be given a certain amount ofcurvature with its convex side facing upstream of course.

The ground after having been excavated down to the solid stratumaccording to the adopted plan and in accordance with the rules of theart, is then dried as far as it is ossible. If any moisture remains, avery lig t layer of basalt ballast Will prevent any excessive formationof air bubbles, The casting operations may then begin.

The furnaces may be fixed or portable. In the former case they should beerected at the most convenient points in the immediate neighborhood, ofthe structure to be built. They may be of widely varying types; in somecases it may be best to employ an electric furnace. Generall however, itis preferred to use a cupola rnace, when Specification of LettersPatent.

Patented Feb. 1'7, 1920.

Application filed November 5, 1918. Serial No. 261,813.

the dam tobe built is of large size, and it is not feared to change thechemical composition of the material within certain limits, it

will be an advantage to choose apparatus of the blast furnace type.

These allow of a much better utilization of the heat, and by thereduction of a part of the iron oxids of the basalt, they produce acertain amount of iron that can be sold at a fairish price.

The molten basalt is to be convoyed to the points where it is to becast, by means of portable fore-'hearths, ladles or other suitablevessels ada ted to travel on aerial cable ways or on rai s su ported onscaffolds on each side of the worll.

Portable furnaces, where their use is necessitatedby exceptionalcircumstances will be mounted on balls or on wheels and will be adaptedto travel along the. rails on the scaffolds.

In a case where the width of the dam should render it necessary, thesaid furnaces would be located on traveling bridges provided with railsextending right across the dam, these traveling bridges bein in theirturn adapted to travel on the railsof the scaffolds. -In this manner andowing to the two-fold mobility of the furnaces along the travelingbridges, and of the traveling bridges along the entire structure, thereis no point of the dam that cannot be reached by the casting operation.The apparatuses are charged by means of aerial cable ways or any othersuitable means.

It is to'be understood that a plurality of furnaces may be arranged totravel simultaneously, and that arrangements are made for removing andreplacing any of the apparatusthat may require repair.

It is also to be .understood that the traveling bridges may be used incertain cases for the conveyance of ladles charged with material thathas been melted in fixed furnaces.

But whatever ma be the system of melting and conveyance that is adopted,it will be necessary, exce t in rare cases, to employ only a non-bub lymaterial, which on cooling will form a dense rock of reat strength. Thiscondition is easily sat sfied by basalt which in the state of liquidfusion, allows of a rapid escape of its bubbles in the vessels inwhichit is received as it is runfrom the furnaces.

The shape to be given to the dam is produced in a very simple manner. Solong as the work is being built u in the excavation, "the sides of thelatter w' I serve as the mold. On leaving the excavation the fluidmaterial is contained at suitable points by a line of frames set side byside lined with bricks which may be porous or non-porous, but-are welltalced -or rubbed with cinder if it is desired to prevent adhesion. Theframes are allowed to remain in place for a certain number of days so asto prevent thesides of the structure from cooling too quickly, afterwhich they may be removed for re-use.

Instead of bucks, there may be employed slabs of baked earth, cast iron,or plates of.

very-dry cement orother means. In some cases where there is no objectionto having sides of very irregular shape and w1th a slope, molding may bedispensed w1th altogether.-

These preliminary arrangements having been made, the following is adescription of the manner of making the block,.and how it is possible bymeans of daily castings .25 to produce a monolithic structureconstituting a real natural rock having enormous strength of resistance.p

' When a castin of molten basalt has not great thickness, t e materials00n solidifies,

but if while it is still hot, although its temperature has fallen tobelow red heat, a fresh 'castin is poured .upon its surface, its moresuper cial parts will become melted again and an intimate union will beproduced between the two masses. Consequently as the dam increases inheight, the quantity of m'aterial that is added every day to its surfacewill become united by autogenous welding to the underlying block and 40will form absolutely one piece therewith.

Moreover it will serve to complete the devitrification of those portionsof the mass of the preceding casting which by having cooled too quickly,may have acquired a vitreous character.

One condition however which must be considered as beingalmost essentialto success, is this, namely, the work of constructing the dam when oncebegun, must never be in terrupted, in other words a sufficient quantityof material must be poured upon each point of the surface of themonolithic structure before the temperature at that point has fallen tooclose to the temperature of the atmosphere. Consequently every care mustbe taken in every respect to assure that the dam shall receive each dayon its surface so much fresh material as will raise the height of thedam by at least some decimeters approximately uniformly throughout itsex-- tent.

Therefore unless the daily addition of materlal is great, it isnecessary at least to provide some protection against a rapid cooling ofthe liquid basalt that is being continually poured upon the dam incourse of construction, Such protection .is necessary 1n order that theautogenous welding shallhold.

Such protection is further necessary to assure the devitrification ofthe material whereby the rock regains all its resisting. power. Forthispurpose a layer of hot an relatively stagnant air is formed at its sur-,face by means which may yary considerably.

Among such means, there is one which has proved its efficiency, namelythe arrangement of frames lined with porous bricks supported by theirends directly upon the scaffolds when the width of the work is not toogreat, or resting on stretched ropes or on a metal framework providedfor this purpose in other cases, but always arranged side by side insuch a manner as to form a continuous horizontal screen for a smallhelght above the surface of the basalt. When a casting operation has tobe done at any point, the corresponding frame will be temporarily movedaside.

If by reason of untoward circumstances the work has been discontinuedfor so long a time asto cause a complete cooling of its surface, it willbe necessary to resume the pourings in the ordinary way, and then some.hours afterward to break up the product of In most cases it will beadvantageous to employ reinforced basalt instead of ordinary basalt. Theresisting power of the block will be greatly increased thereby, while inthe case of an interruption of the construction 'the resumption of thework .will also be facilitated.

With a view to economy, there ma be introduced into the molten materialeither before or after the casting in sir/w, a certain quantity ofbasalt, granite, flint or other rocks that will not be liable to becomedecomposed by the tem erature of the bath, such rocks should e coarselycrushed. These fragments will unite to form one piece with the basalt onthe cooling of the I latter. In order to prevent the inconvenientformation of bubbles, only lumps should be used which have'first beenfreed by suitable heating from their natural water content and thegreater portion of their occluded gases, and they are mixed withthe'basalt while they are still hot. i

As soon as the monolithic block has reached a certain height it may becalled upon to support its own scaffolding. For this purpose pieces ofiron in suitable number and of suitable strength are inserted in theblock; holes and recessed or projecting parts are formed at suitablepoints; all for the purpose of providing supports for the scaffolds atthe sides. The stepped sloping side of the actual dam may even beutilized for this purpose.

It is scarcely necessary to mention any of the advantages afforded bythe use of monolithic basalt structures. The enormous strength of thismaterial will allow of re-- ducing appreciably the total cubic contentof such structures compared with the cubic content of the ordinarymasonry or brickwork which it replaces, while increasing however themargin of safety. No upkeep, and practically no watching are required.

The improved method allows of building bridges, viaducts, various worksof fortification such as parapets, escarpment and counter-escarpmentwalls, open czaponieres, aprons for armor, emplacements for large guns,and even casemates because basalt, especially when reinforced, is verysuitable for the construction of roofs or vaultings. It may also beemployed in the construction of wall foundations, and also entire walls,even for dwellings, which, in addition to their unshakable firmness.have the advantage of being capable of very rich ornamentation. Thisenumeration has no limiting force whatever, because any structures ofthe kind hercinbefore referred to. can be constructed of the samematerial and by the same method, barring slight modifications accordingto the circumstances of each case. Having now particularly described andascertained the nature of our said invention, and in what manner thesame is to be performed We declare that What we claim is 1. A method ofconstructing constructional works, dams, barrages, fortifications,bridges and the like structures, which consists in casting molten basaltin successive superposed layers in the actual space which the desiredstructure is to occupy, each new layer being cast while the precedinglayer is still sufficiently hot to become welded to the said new layer,whereby the whole forms a monolithic structure.

2. A method of constructing constructional works, dams, barrages,fortifications, bridges and the like structures, which consists incasting molten basalt in successive superposed layers in the actualspace which the desired structure is to occupy, the cooling of the topsurface of the structure as it is being built, being reduced by means ofa screen which placed upon it and which retains a layer of air on thecast basalt.

3. A method of constructing constructional works, dams and the likestructures, which consists in casting molten basalt in successivesuperposed layers in the actual space to be occupied by the desiredstructure, and incorporating, heated stones successively into the layersof basalt while the said layers are still fluid.

4. A method of constructing constructional works. dams. and the likestructures, which consists in casting molten basalt in successivesuperposed layers in the actual space to be occupied by the desiredstructure, from casting appliances that are adapted to travel onscaffolds which rest on the actual structure and which are raisedaccording as the said structure increases in height.

FRANCOIS RIBBE. PAUL DHE.

